April 22, 1999 Pratt Conference Room, Perkin G-04, 12:30 pm
Dust in Elliptical Galaxies
Dr. Michael Wise, MIT
Contrary to historical viewpoints, it is clear from optical and
infrared observations that elliptical galaxies contain substantial
amounts of dust. A recent survey of HST data on ellipticals from
Cycle 1-3 indicate that 60%-80% of all ellipticals exhibit central
dust features. However, estimates for the amount of dust based on
such optically visible structures account for only 1%-10% of the
total amount of dust detected by IRAS. The remainder of the dust
seen by IRAS may be present either in a smooth, diffuse component
or at larger radii. Dust in the cores of ellipticals can have a
dramatic impact on the observed properties of these systems and
their interpretation. In effect, all broad-band observations of
elliptical galaxy cores may be age-metallicity-dust degenerate.
Such distributions could complicate our understanding of the
dynamical evolution of the central regions of these objects.
In this talk, I will discuss the results of some recent theoretical
models of dusty elliptical galaxies and illustrate the effects
such dust populations can have on their observed broad-band
properties. I'll show some examples based on HST observations and
discuss the prospects for unraveling this triple degeneracy.